LIFE HISTORIES OF NORTH AMERICAN DIVING BIRDS. 715 
Dr. Joseph Grinnell (1909) describes a nest found at Glacier Bay, 
Alaska, on July 16, 1907, as follows: 
This was in the rank grass at the edge of a pond a few yards back from the 
shore of one of the small islands on the east side of the bay. The parent was 
seen to swim away from the nesting place, ¢nd by her peculiar actions indicated 
its proximity. There were two eggs on the point of hatching. Instead of the 
usual floating structure, the eggs in this case rested on the bare, wet mud, 
2 feet back from the water’s edge, there being no nesting material whatever. 
Eggs.—The red-throated loon, like others of this genus, regularly 
lays two eggs. Most writers agree that this is the invariable num- 
ber, but Audubon and some others have stated that three eggs are 
often laid. Sets of three must be exceptional, and occasionally one 
egg may be all that a nest contains. Frequently only one young 
bird is hatched, but in such cases the other egg is infertile. 
The egg is “elliptical ovate” or “cylindrical ovate” in shape, 
with occasionally a tendency toward “ovate” or toward “ fusiform.” 
The shell is smooth and somewhat glossy. The ground color is 
“bister” or “sepia” in the darkest eggs, “auburn,” “ Brussels 
brown,” “brownish olive,” “light brownish olive,” or “ Saccardo’s 
umber” in others, and “ Isabella color” or “ deep olive buff” in the 
palest eggs. Some eggs are nearly spotless, but usually they are 
sparingly and irregularly spotted with small spots or with scattering 
larger spots, rarely with irregular blotches, of the darkest shades 
of brown, such as “clove brown” and “blackish brown”; some eggs 
also have underlying spots of various shades of drab and very rarely 
these are the only markings. The measurements of 58 eggs, in the 
United States National Museum, average 72.5 by 45; the eggs show- 
ing the four extremes measure 80 by 47, 79.5 by 48, 62.5 by 41.5, 
and 68 by 40.5 millimeters. 
The period of incubation seems to be unknown; it is probably 
somewhat less than that of the common loon, as it is a smaller species. 
Both Yarrell (1871) and Macgillivray (1852) state that both sexes 
assist in the incubation. Certainly the pairs remain together all 
through the breeding season, to guard the nesting site and to care 
for the young jointly. Macgillivray (1852) says: 
The female continues to sit, crouching over her eggs, until a person comes 
very near, when she starts forward, plunges into the water, and on emerging 
usually takes to wing, but sometimes swims about with great anxiety, as does 
the male, should he happen to be present. On being deprived of their eggs, 
they may be heard for several evenings lamenting their loss with loud melan- 
choly cries. 
Young.—Both parents are very solicitous in the care of the young. 
When danger threatens the old bird sinks her body below the sur- 
face, with only the head and neck stretched up above it, the young 
bird climbs upon her back and she swims away with him to safety. 
